Windows 8.1: System Image (File History)

It's broadly similar to create a System Image in Windows 8.1 as it is in Windows 7 or Windows 10, though the process is called File History here.

To get started, click on the search box by the Start button and search for file history. Click on the file history link that shows up. You can also access it through the Control Panel by going to System and Security > File History.

Once it's open, connect and external hard drive and follow the steps to back up your files. The first backup may take longest, but after that, it is faster, as it only covers files that have since been changed.